First of all, I want to make my position clear: While I always felt a kind of fascination for tattoos and body modifications, I have none myself and never had the inclination to get one. Thus, while I do love the culturally important and imaginative implementations in different media and games, I am not what you'd consider a wholehearted enthusiast for the subject matter, in spite of being aligned with two sub-cultures that heavily rely on tattoos and body-mods. Thus, I'll try to rate this from a skeptic's point of view and mostly in accordance with the contributions to one's game. The book begins with a comprehensive and very well-informed and informative introduction to several roles tattoos can serve in diverse subsets of culture. After this rather intelligent and nice intro, we are subjected to the relevant skills for tattoos/body-mods in one's game world, i.e. 4 Craft-skills, 1 profession and 3 knowledge skills. We also get 27 new feats that span the range from crafting magical and miniature tattoos to "achievement tattoos", i.e. for example bonding tattoos for lovers and friends, tattoos celebrating that you've slain x creatures of a certain type and even one that kind of touched me and makes for a great RPG-opportunity, a tattoo for a fallen friend. From sexy to intimidating a lot of ground is covered and none of the feats felt superfluous. For those so inclined, we also get feats dealing with e.g. scarification.

What about the process of getting/or removing one's tattoos, though? It's depicted in stunning and imaginative detail and provides a plethora of kits and items for said purposes, among them even a gnomish tattoo machine. I actually learned something about the material of the needles from this section, which is always nice.
After the basics have been established, we move on to the truly fantastic and iconic component of the book, magical tattoos. Mechanically, they take up an item-slot and even have an option for spell-tattoos that work as scrolls or a tattoo that can store spells. This section, in contrast to many item-books I've read so far, is actually a good read, thanks to the descriptions provided. Some might even serve as hooks for further adventures, which is always a nice thing for a DM to have. Mechanically, I have nothing to complain about - all of the 57 tattoos are well-balanced and most of them are iconic enough to actually consider using them.
Chapter 3 details so-called Inkantationists, i.e. magically adept tattoo-artists, and provides rules for a new wizard variant, a new sorceror bloodline and a new PrC, the painted one (d8, 4+Int skills, bad BAB (+5 over 10 levels), medium Ref and Will saves, 8 levels of spell-casting and the ability to advance abilities from their old class). We also get 8 new spells, dealing with tattoos and surprisingly, contraception. I enjoyed them immensely, as I belong to the part of the audience that considers the topic of sexuality and childbirth an integral and fertile ground for adventuring. Pardon the pun. For the people who consider themselves rather adherents to the piercing enthusiasts, 13 new magic items, some of which actually made me smile and one even laugh: The Nipple-shield of Stunning pleasantly reminded me of a certain superbowl scandal whose repercussions swept over even to Europe and were considered somewhat bewildering. But don't fret - the other magical items are quite tame and the book remains mature and non-explicit about the topic. A magical device is also presented.
Finally, we get 3 (more or less) secret organizations centered on the topics of tattoos that are concisely detailed in the limited amount of space granted and might serve both as pro-or antagonists along the PCs. Each also features some short, stat-block-less write-ups of characters to help you flesh out the organization in question and provide potential for conflict, be it internally or externally.

Conclusion:
Editing is top-notch, I didn't notice any errors. Formatting and layout are b/w, printer-friendly, clear and I didn't notice a single glitch. The b/w-artwork ranges from cool to rather average and I personally am not a fan of the old-school style of the cover-artwork. I was rather skeptic with regards to balancing issues on whether all the iconic usages of tattoos in fantasy and mythology could be extrapolated to a general, non-setting specific book. Moreover, I wasn't sure whether this book would impress me enough to consider implementing it in my campaign. To cut a long ramble short, the company that brought you THE resource for gear & treasure shops has made magical tattoos not only a cool, but also a rewarding addition to just about any campaign. I wholeheartedly recommend this book to just about anyone. My final verdict will be 5 stars.